1. Field of the Invention
The present invention relates to an embroidery machine and, more particularly, to an embroidery machine incorporating a stitch pattern selecting system and capable of stitching an embroidery in a desired size.
2. Description of the Related
As shown in FIG. 2, a known embroidery machine has a bed 1, a post 2 standing in the right-hand end of the bed 1, an arm 3 laterally extending from the upper end of the post 2 over the bed 1, and a sewing head 4 attached to the extremity of the arm 3. The arm 3 is provided with a needle bar driving mechanism, not shown, for vertically reciprocating a needle bar 5 holding a needle 6 on its lower end, a needle bar swinging mechanism, not shown, for swinging the needle bar 5 in a direction perpendicular to a feed direction in which a workpiece is fed, a thread take-up lever driving mechanism, not shown, for vertically swinging a thread take-up lever 5 in synchronism with the vertical reciprocation of the needle bar 5, and the associated parts. A main motor 14 drives the needle bar driving mechanism, and a stepping motor 15 drives the thread take-up lever driving mechanism.
A liquid crystal display 10 is put on the front surface of the arm 3 to display symbols representing various pattern elements and stitching functions of the embroidery machine M. Touch keys 11 serving also as transparent electrodes are arranged on the front surface of the liquid crystal display 10 at positions corresponding to the symbols. The touch key 11 corresponding to a symbol representing a desired pattern element is depressed to select the desired pattern element. The start/stop key (hereinafter, referred to as "S/S key") 12 of a start/stop switch (hereinafter, referred to as "S/S switch") for starting and stopping a stitching operation is disposed on the sewing head 4.
An embroidery unit 30 is mounted on the left-hand portion of the bed 1. The embroidery unit 30 is provided with an embroidery table 31 capable of moving along a Y-axis parallel to the feed direction in which a workpiece is fed and along an X-axis perpendicular to the Y-axis. An embroidery frame, not shown, for detachably holding a workpiece is mounted detachably on the embroidery table 31. A first stepping motor 32 for driving the embroidery table 31 to move along the X-axis and a second stepping motor 33 for driving the embroidery table 31 to move along the Y-axis are disposed within the main frame 32 of the embroidery unit 30. The stepping motors 32 and 33 and the needle bar 5 are driven according to driving signals provided by the embroidery machine M to stitch a desired stitch pattern on the workpiece held on the embroidery frame.
Referring to FIG. 3, showing the configuration of an embroidery machine, switches operated by the touch keys 11 and the S/S switch operated by the S/S key 12 are connected to a CPU 23. The main motor 14, the stepping motor 18 for driving the needle bar for swing motion, a display controller (LCDC) 20 for controlling the liquid crystal display (LCD) 10, and the first stepping motor 32 and second stepping motor 33 of the embroidery unit 30 are controlled by the CPU 23. Data including embroidery data to be displayed on the liquid crystal display 10 is stored in a ROM 24. A RAM 25 stores embroidery data temporarily.
When the embroidery machine M is connected to a power source, a pattern element selection picture as shown in FIG. 7(a) is displayed on the liquid crystal display 10. If necessary, a page up key 40 or a page down key 41 is operated to display a picture including desired pattern elements. A touch key corresponding to a desired pattern element displayed on the liquid crystal display 10 is depressed to select the desired pattern element. A cancel key 43 is depressed to cancel the selected pattern element. Thus, a desired stitch pattern consisting of pattern elements can be selected.
When thus selecting a desired stitch pattern, the CPU 23 determines if the desired stitch pattern can be formed within a predetermined available area. The CPU 23 selects the desired stitch pattern when the desired stitch pattern can be formed within the predetermined available area or gives an error signal to the liquid crystal display 10 when the desired stitch pattern cannot be formed within the predetermined available area. A stitching scale can be selected by operating a scale key 42. A middle scale mode in which the desired stitch pattern is stitched on a middle scale is selected (FIG. 7(b)) when the scale key 42 in a state shown in FIG. 7(a) is depressed, and a small scale mode in which the desired stitch pattern is stitched on a small scale is selected (FIG. 7(c)) when the scale key 42 in a state shown in FIG. 7(b) is depressed. The CPU 23 gives an error signal to the liquid crystal display 10 to inhibit the selection of the scale if the desired stitch pattern cannot be formed on the selected scale in the available area.
For example, when selecting a stitch pattern "AB" as shown in FIG. 8, touch keys 46 and 47 respectively corresponding to the pattern elements "A" and "B" are depressed successively. The selected scale changes sequentially in order of "small".fwdarw."large".fwdarw."middle".fwdarw."small" every time the scale key 42 is depressed.
For example, suppose that a stitch pattern "ABCD" and the small scale mode have been selected, and it is desired to change the small scale mode for the middle scale mode. Then, the CPU 12 tries first to select the large scale mode. However, since the stitch pattern "ABCD" cannot be formed in the large scale within the predetermined available area, the CPU 12 sends an error signal to the liquid crystal display 10. Therefore, when the middle scale mode is desired, the operator must cancel the character "D," depress the scale key 42 twice to change the scale from "small" via "large" to "middle," and add the character "D" again to "ABC" to select the stitch pattern "ABCD," which is a troublesome and inefficient operation.